Respostas

2014-02-27T15:04:11-03:00
1)4× - 4y = 8
2)-x - y = 4
 
2)-x=4+y
x=-4-y
1)4(-4-y)-4y=8
-16-4y-4y=8
-8y=8+16
-8y=24
-y=24/8
-y=3 (-1)
y=-3

x=4-y
x=4-3
x=1